If I remember correctly, Rival Ball searches for board pack installations through a file named dirs.cfg, which specifies a list of possible directories where DX-Ball 2 could have been installed. However, this file may fail in its purpose if you're using a language localized version of Windows, as the Program Files directory will take on a localized name. I believe Microsoft changed their language localizations as of Windows Vista, so that localized directory names are merely masking the actual system names. But I don't know about Windows 7, though.

Regardless, there should be two ways to resolve this issue. First of all, you want to know where you have installed your DX-Ball 2 board packs, as this information is needed for both solutions:

Start by right-clicking your DX-Ball 2 shortcut, and choose Properties from the drop-down list. In the shortcut's properties window, click the Find Target button. This should open the directory where DX-Ball 2 and your board-packs were installed.

Now, for the first method, in accordance to how things were meant to work, open the Boards sub directory. Click on the address bar of the window to select the path, then right-click this text and select Copy from the drop-down list. This is the path that you want to be listed in Rival Ball's dirs.cfg file, for the game to be able to detect your board packs.

To locate dirs.cfg, you need to find the target directory for Rival Ball. So proceed as you did with DX-Ball 2, by opening the properties of your Rival Ball shortcut and clicking Find Target.

When you try to open dirs.cfg, Windows may ask you to choose an appropriate application for the file type. Just open the file in Notepad, and you'll be fine. You should see a list of different directory paths within this file. All you have to do now is paste the path that you copied from the DX-Ball 2 directory to the bottom of the list. Finally, save the file and close it.

Do the board packs appear in Rival Ball now?

If for whatever reason they chose to stay on vacation, you can alternatively force a copy of the board-set files into the Boards sub directory of Rival Ball. So, for the second method, start by going back to your DX-Ball 2 directory. Then right-click the Boards sub directory and select Copy. Go back to the Rival Ball directory again and right-click on a blank space. Select Paste from the drop-down list and allow any possible duplicate files to be replaced. This should now copy all of your DX-Ball 2 board packs directly into Rival Ball.

Ah, thanks for bringing up dirs.cfg. I suspect the original poster has solved their problem already, but it's useful for posterity.

I could be wrong, but I believe Windows only localizes the folder name when it displays it; under the hood it should still be "Program Files" or "Program Files (x86)".

However, there are certainly ways that dirs.cfg could fail. The most common causes of this are:

1) You have a version of DX-Ball 2 that predates 64-bit Windows, in which case your dirs.cfg will be missing the "Program Files (x86)" folders. In this case, just installer the latest version from the Download Centre and you'll be good to go.

2) If you installed your game in a non-default location, unfortunately Rival Ball won't know where to look. The easiest solution is simply to uninstall and reinstall to the default location, but you can also edit your dirs.cfg file or manually copy the boards into your Rival Ball directory as zephyr explained, if you're comfortable with that.